I have used my EOS1N in Av mode for decades; I don't use it on "full auto" mode because, being a high end professional camera, it doesn't have such a mode.
Many years ago an EOS 5 was used but still Av mode and occasional P for Professional mode (!) was used. It is the way I was trained: not to rely on automation but to the majority of thinking and analysis myself. And that has been my mainstay all the way, even now in medium format.